A one-pot synthesis of pyridinium-based ionic porous organic polymers for efficient CO2 catalytic conversion

Abstract

Porous organic polymers (POPs) have been regarded as promising recyclable catalysts for improving the efficiency of CO₂ and epoxide cycloaddition due to their diverse catalytic functionality, abundant active sites and good chemical stability. Nevertheless, the need for co-catalysts and metals, the harsh reaction conditions and the complicated preparation methods have greatly limited the wide application of POPs. Herein, we demonstrated the synthesis of one type of pyridinium-based ionic POP named TE-POPs through the one-pot method for use as efficient heterogeneous catalysts for CO₂ cycloaddition. The results indicated that the TE-POPs with high thermal stability and excellent chemical stability exhibited the highest CO₂ adsorption capacity (32.3 cm³ g⁻¹ at 298 K) among all the reported vinylene-linked POP materials. Importantly, under the optimized conditions of 90 °C, 0.1 MPa CO₂ for 20 h, the TE-POPs with multiple active sites could efficiently catalyze the CO₂ and epichlorohydrin to chloropropylene carbonate with a yield of 96% without the presence of any co-catalysts or metals. Furthermore, it displayed a wide substrate scope of different epoxides and excellent recyclability, which made it a promising heterogeneous catalyst for the CO₂ cycloaddition reaction.